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-rw-r--r--mm/kasan/generic.c519
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diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
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--- /dev/null
+++ b/mm/kasan/generic.c
@@ -0,0 +1,519 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file contains core generic KASAN code.
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
+ *
+ * Some code borrowed from https://github.com/xairy/kasan-prototype by
+ * Andrey Konovalov <andreyknvl@gmail.com>
+ */
+
+#include <linux/export.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/kasan.h>
+#include <linux/kernel.h>
+#include <linux/kfence.h>
+#include <linux/kmemleak.h>
+#include <linux/linkage.h>
+#include <linux/memblock.h>
+#include <linux/memory.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
+#include <linux/slab.h>
+#include <linux/stacktrace.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/vmalloc.h>
+#include <linux/bug.h>
+
+#include "kasan.h"
+#include "../slab.h"
+
+/*
+ * All functions below always inlined so compiler could
+ * perform better optimizations in each of __asan_loadX/__assn_storeX
+ * depending on memory access size X.
+ */
+
+static __always_inline bool memory_is_poisoned_1(unsigned long addr)
+{
+ s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr);
+
+ if (unlikely(shadow_value)) {
+ s8 last_accessible_byte = addr & KASAN_GRANULE_MASK;
+ return unlikely(last_accessible_byte >= shadow_value);
+ }
+
+ return false;
+}
+
+static __always_inline bool memory_is_poisoned_2_4_8(unsigned long addr,
+ unsigned long size)
+{
+ u8 *shadow_addr = (u8 *)kasan_mem_to_shadow((void *)addr);
+
+ /*
+ * Access crosses 8(shadow size)-byte boundary. Such access maps
+ * into 2 shadow bytes, so we need to check them both.
+ */
+ if (unlikely(((addr + size - 1) & KASAN_GRANULE_MASK) < size - 1))
+ return *shadow_addr || memory_is_poisoned_1(addr + size - 1);
+
+ return memory_is_poisoned_1(addr + size - 1);
+}
+
+static __always_inline bool memory_is_poisoned_16(unsigned long addr)
+{
+ u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
+
+ /* Unaligned 16-bytes access maps into 3 shadow bytes. */
+ if (unlikely(!IS_ALIGNED(addr, KASAN_GRANULE_SIZE)))
+ return *shadow_addr || memory_is_poisoned_1(addr + 15);
+
+ return *shadow_addr;
+}
+
+static __always_inline unsigned long bytes_is_nonzero(const u8 *start,
+ size_t size)
+{
+ while (size) {
+ if (unlikely(*start))
+ return (unsigned long)start;
+ start++;
+ size--;
+ }
+
+ return 0;
+}
+
+static __always_inline unsigned long memory_is_nonzero(const void *start,
+ const void *end)
+{
+ unsigned int words;
+ unsigned long ret;
+ unsigned int prefix = (unsigned long)start % 8;
+
+ if (end - start <= 16)
+ return bytes_is_nonzero(start, end - start);
+
+ if (prefix) {
+ prefix = 8 - prefix;
+ ret = bytes_is_nonzero(start, prefix);
+ if (unlikely(ret))
+ return ret;
+ start += prefix;
+ }
+
+ words = (end - start) / 8;
+ while (words) {
+ if (unlikely(*(u64 *)start))
+ return bytes_is_nonzero(start, 8);
+ start += 8;
+ words--;
+ }
+
+ return bytes_is_nonzero(start, (end - start) % 8);
+}
+
+static __always_inline bool memory_is_poisoned_n(unsigned long addr,
+ size_t size)
+{
+ unsigned long ret;
+
+ ret = memory_is_nonzero(kasan_mem_to_shadow((void *)addr),
+ kasan_mem_to_shadow((void *)addr + size - 1) + 1);
+
+ if (unlikely(ret)) {
+ unsigned long last_byte = addr + size - 1;
+ s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
+
+ if (unlikely(ret != (unsigned long)last_shadow ||
+ ((long)(last_byte & KASAN_GRANULE_MASK) >= *last_shadow)))
+ return true;
+ }
+ return false;
+}
+
+static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
+{
+ if (__builtin_constant_p(size)) {
+ switch (size) {
+ case 1:
+ return memory_is_poisoned_1(addr);
+ case 2:
+ case 4:
+ case 8:
+ return memory_is_poisoned_2_4_8(addr, size);
+ case 16:
+ return memory_is_poisoned_16(addr);
+ default:
+ BUILD_BUG();
+ }
+ }
+
+ return memory_is_poisoned_n(addr, size);
+}
+
+static __always_inline bool check_region_inline(unsigned long addr,
+ size_t size, bool write,
+ unsigned long ret_ip)
+{
+ if (!kasan_arch_is_ready())
+ return true;
+
+ if (unlikely(size == 0))
+ return true;
+
+ if (unlikely(addr + size < addr))
+ return !kasan_report(addr, size, write, ret_ip);
+
+ if (unlikely((void *)addr <
+ kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
+ return !kasan_report(addr, size, write, ret_ip);
+ }
+
+ if (likely(!memory_is_poisoned(addr, size)))
+ return true;
+
+ return !kasan_report(addr, size, write, ret_ip);
+}
+
+bool kasan_check_range(unsigned long addr, size_t size, bool write,
+ unsigned long ret_ip)
+{
+ return check_region_inline(addr, size, write, ret_ip);
+}
+
+bool kasan_byte_accessible(const void *addr)
+{
+ s8 shadow_byte;
+
+ if (!kasan_arch_is_ready())
+ return true;
+
+ shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(addr));
+
+ return shadow_byte >= 0 && shadow_byte < KASAN_GRANULE_SIZE;
+}
+
+void kasan_cache_shrink(struct kmem_cache *cache)
+{
+ kasan_quarantine_remove_cache(cache);
+}
+
+void kasan_cache_shutdown(struct kmem_cache *cache)
+{
+ if (!__kmem_cache_empty(cache))
+ kasan_quarantine_remove_cache(cache);
+}
+
+static void register_global(struct kasan_global *global)
+{
+ size_t aligned_size = round_up(global->size, KASAN_GRANULE_SIZE);
+
+ kasan_unpoison(global->beg, global->size, false);
+
+ kasan_poison(global->beg + aligned_size,
+ global->size_with_redzone - aligned_size,
+ KASAN_GLOBAL_REDZONE, false);
+}
+
+void __asan_register_globals(struct kasan_global *globals, size_t size)
+{
+ int i;
+
+ for (i = 0; i < size; i++)
+ register_global(&globals[i]);
+}
+EXPORT_SYMBOL(__asan_register_globals);
+
+void __asan_unregister_globals(struct kasan_global *globals, size_t size)
+{
+}
+EXPORT_SYMBOL(__asan_unregister_globals);
+
+#define DEFINE_ASAN_LOAD_STORE(size) \
+ void __asan_load##size(unsigned long addr) \
+ { \
+ check_region_inline(addr, size, false, _RET_IP_); \
+ } \
+ EXPORT_SYMBOL(__asan_load##size); \
+ __alias(__asan_load##size) \
+ void __asan_load##size##_noabort(unsigned long); \
+ EXPORT_SYMBOL(__asan_load##size##_noabort); \
+ void __asan_store##size(unsigned long addr) \
+ { \
+ check_region_inline(addr, size, true, _RET_IP_); \
+ } \
+ EXPORT_SYMBOL(__asan_store##size); \
+ __alias(__asan_store##size) \
+ void __asan_store##size##_noabort(unsigned long); \
+ EXPORT_SYMBOL(__asan_store##size##_noabort)
+
+DEFINE_ASAN_LOAD_STORE(1);
+DEFINE_ASAN_LOAD_STORE(2);
+DEFINE_ASAN_LOAD_STORE(4);
+DEFINE_ASAN_LOAD_STORE(8);
+DEFINE_ASAN_LOAD_STORE(16);
+
+void __asan_loadN(unsigned long addr, size_t size)
+{
+ kasan_check_range(addr, size, false, _RET_IP_);
+}
+EXPORT_SYMBOL(__asan_loadN);
+
+__alias(__asan_loadN)
+void __asan_loadN_noabort(unsigned long, size_t);
+EXPORT_SYMBOL(__asan_loadN_noabort);
+
+void __asan_storeN(unsigned long addr, size_t size)
+{
+ kasan_check_range(addr, size, true, _RET_IP_);
+}
+EXPORT_SYMBOL(__asan_storeN);
+
+__alias(__asan_storeN)
+void __asan_storeN_noabort(unsigned long, size_t);
+EXPORT_SYMBOL(__asan_storeN_noabort);
+
+/* to shut up compiler complaints */
+void __asan_handle_no_return(void) {}
+EXPORT_SYMBOL(__asan_handle_no_return);
+
+/* Emitted by compiler to poison alloca()ed objects. */
+void __asan_alloca_poison(unsigned long addr, size_t size)
+{
+ size_t rounded_up_size = round_up(size, KASAN_GRANULE_SIZE);
+ size_t padding_size = round_up(size, KASAN_ALLOCA_REDZONE_SIZE) -
+ rounded_up_size;
+ size_t rounded_down_size = round_down(size, KASAN_GRANULE_SIZE);
+
+ const void *left_redzone = (const void *)(addr -
+ KASAN_ALLOCA_REDZONE_SIZE);
+ const void *right_redzone = (const void *)(addr + rounded_up_size);
+
+ WARN_ON(!IS_ALIGNED(addr, KASAN_ALLOCA_REDZONE_SIZE));
+
+ kasan_unpoison((const void *)(addr + rounded_down_size),
+ size - rounded_down_size, false);
+ kasan_poison(left_redzone, KASAN_ALLOCA_REDZONE_SIZE,
+ KASAN_ALLOCA_LEFT, false);
+ kasan_poison(right_redzone, padding_size + KASAN_ALLOCA_REDZONE_SIZE,
+ KASAN_ALLOCA_RIGHT, false);
+}
+EXPORT_SYMBOL(__asan_alloca_poison);
+
+/* Emitted by compiler to unpoison alloca()ed areas when the stack unwinds. */
+void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom)
+{
+ if (unlikely(!stack_top || stack_top > stack_bottom))
+ return;
+
+ kasan_unpoison(stack_top, stack_bottom - stack_top, false);
+}
+EXPORT_SYMBOL(__asan_allocas_unpoison);
+
+/* Emitted by the compiler to [un]poison local variables. */
+#define DEFINE_ASAN_SET_SHADOW(byte) \
+ void __asan_set_shadow_##byte(const void *addr, size_t size) \
+ { \
+ __memset((void *)addr, 0x##byte, size); \
+ } \
+ EXPORT_SYMBOL(__asan_set_shadow_##byte)
+
+DEFINE_ASAN_SET_SHADOW(00);
+DEFINE_ASAN_SET_SHADOW(f1);
+DEFINE_ASAN_SET_SHADOW(f2);
+DEFINE_ASAN_SET_SHADOW(f3);
+DEFINE_ASAN_SET_SHADOW(f5);
+DEFINE_ASAN_SET_SHADOW(f8);
+
+/* Only allow cache merging when no per-object metadata is present. */
+slab_flags_t kasan_never_merge(void)
+{
+ if (!kasan_requires_meta())
+ return 0;
+ return SLAB_KASAN;
+}
+
+/*
+ * Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
+ * For larger allocations larger redzones are used.
+ */
+static inline unsigned int optimal_redzone(unsigned int object_size)
+{
+ return
+ object_size <= 64 - 16 ? 16 :
+ object_size <= 128 - 32 ? 32 :
+ object_size <= 512 - 64 ? 64 :
+ object_size <= 4096 - 128 ? 128 :
+ object_size <= (1 << 14) - 256 ? 256 :
+ object_size <= (1 << 15) - 512 ? 512 :
+ object_size <= (1 << 16) - 1024 ? 1024 : 2048;
+}
+
+void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
+ slab_flags_t *flags)
+{
+ unsigned int ok_size;
+ unsigned int optimal_size;
+
+ if (!kasan_requires_meta())
+ return;
+
+ /*
+ * SLAB_KASAN is used to mark caches that are sanitized by KASAN
+ * and that thus have per-object metadata.
+ * Currently this flag is used in two places:
+ * 1. In slab_ksize() to account for per-object metadata when
+ * calculating the size of the accessible memory within the object.
+ * 2. In slab_common.c via kasan_never_merge() to prevent merging of
+ * caches with per-object metadata.
+ */
+ *flags |= SLAB_KASAN;
+
+ ok_size = *size;
+
+ /* Add alloc meta into redzone. */
+ cache->kasan_info.alloc_meta_offset = *size;
+ *size += sizeof(struct kasan_alloc_meta);
+
+ /*
+ * If alloc meta doesn't fit, don't add it.
+ * This can only happen with SLAB, as it has KMALLOC_MAX_SIZE equal
+ * to KMALLOC_MAX_CACHE_SIZE and doesn't fall back to page_alloc for
+ * larger sizes.
+ */
+ if (*size > KMALLOC_MAX_SIZE) {
+ cache->kasan_info.alloc_meta_offset = 0;
+ *size = ok_size;
+ /* Continue, since free meta might still fit. */
+ }
+
+ /*
+ * Add free meta into redzone when it's not possible to store
+ * it in the object. This is the case when:
+ * 1. Object is SLAB_TYPESAFE_BY_RCU, which means that it can
+ * be touched after it was freed, or
+ * 2. Object has a constructor, which means it's expected to
+ * retain its content until the next allocation, or
+ * 3. Object is too small.
+ * Otherwise cache->kasan_info.free_meta_offset = 0 is implied.
+ */
+ if ((cache->flags & SLAB_TYPESAFE_BY_RCU) || cache->ctor ||
+ cache->object_size < sizeof(struct kasan_free_meta)) {
+ ok_size = *size;
+
+ cache->kasan_info.free_meta_offset = *size;
+ *size += sizeof(struct kasan_free_meta);
+
+ /* If free meta doesn't fit, don't add it. */
+ if (*size > KMALLOC_MAX_SIZE) {
+ cache->kasan_info.free_meta_offset = KASAN_NO_FREE_META;
+ *size = ok_size;
+ }
+ }
+
+ /* Calculate size with optimal redzone. */
+ optimal_size = cache->object_size + optimal_redzone(cache->object_size);
+ /* Limit it with KMALLOC_MAX_SIZE (relevant for SLAB only). */
+ if (optimal_size > KMALLOC_MAX_SIZE)
+ optimal_size = KMALLOC_MAX_SIZE;
+ /* Use optimal size if the size with added metas is not large enough. */
+ if (*size < optimal_size)
+ *size = optimal_size;
+}
+
+struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache,
+ const void *object)
+{
+ if (!cache->kasan_info.alloc_meta_offset)
+ return NULL;
+ return (void *)object + cache->kasan_info.alloc_meta_offset;
+}
+
+struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache,
+ const void *object)
+{
+ BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32);
+ if (cache->kasan_info.free_meta_offset == KASAN_NO_FREE_META)
+ return NULL;
+ return (void *)object + cache->kasan_info.free_meta_offset;
+}
+
+void kasan_init_object_meta(struct kmem_cache *cache, const void *object)
+{
+ struct kasan_alloc_meta *alloc_meta;
+
+ alloc_meta = kasan_get_alloc_meta(cache, object);
+ if (alloc_meta)
+ __memset(alloc_meta, 0, sizeof(*alloc_meta));
+}
+
+size_t kasan_metadata_size(struct kmem_cache *cache)
+{
+ if (!kasan_requires_meta())
+ return 0;
+ return (cache->kasan_info.alloc_meta_offset ?
+ sizeof(struct kasan_alloc_meta) : 0) +
+ ((cache->kasan_info.free_meta_offset &&
+ cache->kasan_info.free_meta_offset != KASAN_NO_FREE_META) ?
+ sizeof(struct kasan_free_meta) : 0);
+}
+
+static void __kasan_record_aux_stack(void *addr, bool can_alloc)
+{
+ struct slab *slab = kasan_addr_to_slab(addr);
+ struct kmem_cache *cache;
+ struct kasan_alloc_meta *alloc_meta;
+ void *object;
+
+ if (is_kfence_address(addr) || !slab)
+ return;
+
+ cache = slab->slab_cache;
+ object = nearest_obj(cache, slab, addr);
+ alloc_meta = kasan_get_alloc_meta(cache, object);
+ if (!alloc_meta)
+ return;
+
+ alloc_meta->aux_stack[1] = alloc_meta->aux_stack[0];
+ alloc_meta->aux_stack[0] = kasan_save_stack(GFP_NOWAIT, can_alloc);
+}
+
+void kasan_record_aux_stack(void *addr)
+{
+ return __kasan_record_aux_stack(addr, true);
+}
+
+void kasan_record_aux_stack_noalloc(void *addr)
+{
+ return __kasan_record_aux_stack(addr, false);
+}
+
+void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags)
+{
+ struct kasan_alloc_meta *alloc_meta;
+
+ alloc_meta = kasan_get_alloc_meta(cache, object);
+ if (alloc_meta)
+ kasan_set_track(&alloc_meta->alloc_track, flags);
+}
+
+void kasan_save_free_info(struct kmem_cache *cache, void *object)
+{
+ struct kasan_free_meta *free_meta;
+
+ free_meta = kasan_get_free_meta(cache, object);
+ if (!free_meta)
+ return;
+
+ kasan_set_track(&free_meta->free_track, GFP_NOWAIT);
+ /* The object was freed and has free track set. */
+ *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREETRACK;
+}